Papers by Siew Young Quek
Identification and Determination of Compounds Unique to Hericium in an Edible New Zealand Mushroom Hericium novae-zealandiae
Food Analytical Methods, Aug 16, 2021
Hericium novae-zealandiae is a native mushroom traditionally consumed by the indigenous Māori of ... more Hericium novae-zealandiae is a native mushroom traditionally consumed by the indigenous Māori of New Zealand. To study erinacines and hericenones, compounds reported to be unique to the genus Hericium, the small molecular lipophilic constituents of H. novae-zealandiae were evaluated by chromatography coupled with diode array detection. Ethanol was used as an extraction solvent for the detection and quantification of these lipophilic targets. Hericenone C was detected from the ethanol extract of H. novae-zealandiae, but erinacine A and hericenone D were not found present in this extract. A method coupling HPLC with DAD was developed to determine the quantity of hericenone C using a reversed-phase C18 column, with gradient elution consisting of methanol and 0.1% formic acid as mobile phases and detection at 295 nm. The validation conducted of this method included parameters of selectivity, linearity, precision, accuracy and robustness, and all validation results were acceptable. Hericenone C was measured as comprising 0.75 mg/g dry weight of the mushroom. This is the first report of research on erinacine A, hericenone C and hericenone D in H. novae-zealandiae. This is also the first report of an analytical method suitable for the quantification of hericenone C in this species. More compounds unique to Hericium are expected to be reported when further investigations are carried out on this newly studied species of Hericium.
Structured Lipid Functionality and Application
Elsevier eBooks, 2019
Efficient extraction and characterization of pectin from orange peel by a combined surfactant and microwave assisted process
Food Chemistry, Jul 1, 2019
Surfactant and microwave assisted extraction (S-MAE) was used for pectin extraction from orange p... more Surfactant and microwave assisted extraction (S-MAE) was used for pectin extraction from orange peel. First, we optimized the conditions of microwave assisted extraction (MAE), e.g., irradiation time, liquid-to-solid ratio (LSR), and pH on pectin yield (PY), galacturonic acid (GA) content, and degree of esterification (DE) using a Box-Behnken design. Under optimal conditions (pH 1.2, 7.0 min, and 21.5 v/w LSR), we obtained a PY of 28.0 ± 0.5%, which was close to the predicted value (31.1%). Second, we analyzed the effect of surfactant on microwave extraction of pectin. Among the surfactants investigated, Tween-80 (8 g/L, w/v) increased PY by 17.0%. Compared with conventional solvent extraction, S-MAE is a novel and efficient method for pectin extraction, which generated a higher (p < 0.05) PY (32.8%), GA content (78.1%), DE (69.8%), and Mw (286.3 kDa).
Modeling of single droplet drying of noni juice to unveil the drying mechanism
Journal of Nutrition and Food Sciences, May 30, 2018
The Use of Sago Waste for the Sorption of Lead and Copper
Water SA, 1998
... Adsorption has advantages over other methods. ... Activated carbon has been recognised as a h... more ... Adsorption has advantages over other methods. ... Activated carbon has been recognised as a highly effective adsorbent for the treatment of heavy metals in ... Therefore, there is increasing research interest in using alternative low-cost adsorbents. ...
The effect of metabolic stress disinfection and disinfestation (MSDD) on ‘Hass’ avocado fruit physiology and mortality of longtailed mealybug (Pseudococcus longispinus)
Postharvest Biology and Technology, 2012
ABSTRACT Metabolic stress disinfection and disinfestation (MSDD) is a potential quarantine treatm... more ABSTRACT Metabolic stress disinfection and disinfestation (MSDD) is a potential quarantine treatment in which a combination of cycles of rapid decompression and compression are followed by exposure to ethanol vapour under decompression. The response of ‘Hass’ avocado (Persea americana Mill., cv. Hass) to MSDD treatment for control of longtailed mealybug (Pseudococcus longispinus) was investigated. The best treatment for the most resistant life stage (2nd/3rd instars) was 90-min MSDD treatment with 371 mg L−1 ethanol. Early and late season ‘Hass’ avocados were subjected to MSDD treatments (with 371 mg L−1 ethanol), or in air (control). Following the treatments, early season fruit were ripened at 20 °C and 25 °C. Half of the late season fruit were ripened at either 20 °C or 25 °C, and the remainder were stored at 5.5 °C for 6 weeks, then ripened at 20 °C. There were no significant difference in quality and rot incidence between non-treated controls and MSDD-treated fruit. The main disorders found were stem-end and body rots, vascular browning and flesh greying for the stored fruit. There were also no significant differences in fruit respiration rate or ethylene production. Thus, MSDD was shown to be a potentially ‘soft’ disinfestation treatment for surface pests of avocado.Highlights• MSDD is novel disinfestation technique utilizing pressure change, modification of atmosphere and ethanol. • 90 min MSDD treatments with 371 mg L−1 ethanol control all lifestages of longtailed mealybug. • 90 min MSDD treatments with 371 mg L−1 did not significantly reduce fruit quality.
Advances in spray-dried probiotic microcapsules for targeted delivery: a review
Critical Reviews in Food Science and Nutrition, Jul 17, 2023
Microencapsulation of bioactives for functional food development
Journal of Nutrition and Food Sciences, Jul 29, 2016
Powder Technology, Feb 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Food Engineering, Apr 1, 2019
The objective of this research was to study the co-encapsulation of Coenzyme Q 10 (CoQ 10 ) and v... more The objective of this research was to study the co-encapsulation of Coenzyme Q 10 (CoQ 10 ) and vitamin E (VE) using single droplet drying (SDD) and micro-fluidic-jet spray drying (MFJSD), to study the particle formation-structure-function relationships of the microcapsules. Single droplets of selected CoQ 10 and VE-containing emulsions were studied for their particle formation under convective drying (at 70 and 90 °C for 10 min) and rehydration processes using the SDD device. The emulsions were also spray-dried (at 160 and 190 °C) by MFJSD to form monodisperse microcapsules, followed by analyses of powder properties and functionalities. Results from SDD showed emulsion droplets with 30% w/w solids content were associated with earlier crust formation (30 s faster) and less particle shrinkage during drying compared to those with 10% w/w solid content. Comparing the spray-dried microcapsules produced from the emulsions containing 30% and 10% w/w solids content, the former gave larger particle size (172-175 m vs. 116 m), higher microencapsulation efficiency (ME) (98-99% vs. 96%), lower tapped density (0.532-0.599 g/cm 3 vs. 0.406-0.502 g/cm 3 ) and better flow properties . Overall, the CoQ 10 and VE retention, antioxidant capacities and colour of the microcapsules were relatively stable when spray-dried at 190 °C than at 160 °C.
Optimisation of enzymatic hydrolysis for concentration of vitamin E in palm fatty acid distillate
Food Chemistry, Mar 1, 2003
... 10081009. Ong et al., 1994. Ong, ASH, Choo, YM, Goh, SH, &amp; Kam, TS (1994). ... Qures... more ... 10081009. Ong et al., 1994. Ong, ASH, Choo, YM, Goh, SH, &amp; Kam, TS (1994). ... Qureshi et al., 1986. AA Qureshi, WC Burger, DM Peterson and CE Elson , The structure of an inhibitor of cholesterol biosynthesis isolated from barley. ...
Food Chemistry, Apr 1, 2021
Octenyl succinic anhydride esterified waxy corn starches (OSAS) with five different molecular wei... more Octenyl succinic anhydride esterified waxy corn starches (OSAS) with five different molecular weights (MWs) were prepared by enzymatic hydrolysis and their effects on naringin solubility were studied. The MW of OSAS was found to significantly influence the amount of naringin embedded in the complex formed by self-aggregation. OSAS with medium MW (M-OSAS) formed complex with the highest naringin entrapment. This system showed an A L type water phase solubility curve (indicating a 1:1 stoichiometric inclusion complex) and an increase of 848.83 folds in naringin solubility. Further investigation on the interactions between M-OSAS and naringin using FTIR, XRD, DSC and NMR confirmed the encapsulation of naringin into the inner cavity of M-OSAS. TEM and particle size analysis indicated the complex was spherical in shape, having a mean particle size of 257.07 nm and size distribution of 10-1000 nm. This study has provided a basis for solubility enhancement of citrus flavonoids using OSAS.
Food Science and Human Wellness, Mar 1, 2022
Fig fruit is a good source of minerals and crude fibers. The dark-colored fig cultivars rich in a... more Fig fruit is a good source of minerals and crude fibers. The dark-colored fig cultivars rich in anthocyanins are also known with their high polyphenol content. However, although there are many different dark-colored fig cultivars grown in Turkey, the dried fig industry has traditionally been concentrated on drying of several yellow-colored fig cultivars. The aim of this study is to determine the effects of sundrying and oven-drying on some general characteristics, phenolic content and antioxidant capacity of 2 dark-colored (black) and 2 light-colored (yellow) fig cultivars selected from genetic collection of Turkish Fig Research Institute. The figs were obtained by harvesting at the semi-dry stage at 40-50% moisture content and applying sun-drying or oven-drying to reach final moisture content between 20 and 26%. The sun-drying was conducted on mats for 2-3 days under the sun while the oven-drying was applied for 12 h at 60°C and at the air velocity of 0,5 m s -1 . The result of the study clearly showed almost 1,5-2 fold higher total phenolic content and ABTS free radical scavenging based antioxidant capacity of fresh dark-colored figs than fresh light-colored ones. The drying had almost no negative effects on the total phenolic content of both dark-and light-colored figs. The drying also did not have a negative effect on antioxidant capacity of light-colored figs, but it caused a limited reduction (between 20 and 30%) in antioxidant capacity of dark-colored figs due to the well-known heat labile nature of their color compounds anthocyanins. The use of sun-drying or oven-drying did not have a considerably different effect on final phenolic contents and antioxidant capacities of dried figs. This study clearly showed that it is possible to obtain phenolic rich dried figs by use of dark colored fig cultivars such as TR1101 and TR1102.
Lebensmittel-Wissenschaft & Technologie, Apr 1, 2020
Free and glycosidically bound volatiles from two major tomato cultivars (Lycopersicon esculantum ... more Free and glycosidically bound volatiles from two major tomato cultivars (Lycopersicon esculantum L. cv. Alida and Merve) of Turkey were determined. Free volatile compounds were extracted using liquid-liquid microextraction, while bound volatiles were extracted using solid phase extraction. The compounds were analyzed using GC-FID and GC-MS. Alida showed presence of, 39 free and 32 bound aroma compounds again 38 free and 31 bound aroma compounds is Merve. The odor activity values of the volatile compounds suggested that hexanal, (Z)-3-hexenal, (E,Z)-2,4-decadienal, (E,E)-2,4-decadienal and 2-phenylethanol were most significant odorants in both cultivars. Guaiacol and eugenol were flavor contributors for Merve. The norisoprenoids 5,6-epoxy-b-ionone and 3-hydroxy-bionone were observed in free form in tomato. Norisoprenoids, terpenoids, volatile phenols and higher alcohols were present in the glycosidic extract. Among the glycosidically bound compounds, 2-phenylethanol, guaiacol and eugenol were found to be potential contributors to overall tomato flavor upon hydrolysis.
Journal of Food Engineering, Mar 1, 2004
In this study, vitamin E was separated from palm fatty acid distillate by batch adsorption using ... more In this study, vitamin E was separated from palm fatty acid distillate by batch adsorption using an orbital shaker. Silica was used as the adsorbent. Equilibrium of the adsorption process as a function of reaction temperature, agitation rate and silica mass on vitamin E adsorption onto silica was investigated over a range of vitamin E concentration. Lower reaction temperature led to higher vitamin E uptake at equilibrium, indicating that the adsorption process in this study was exothermic. Adsorption capacity increased with the rise in agitation rate. However, in this study the maximum adsorption capacity remained unchanged when silica mass was increased. Generally, non-linear regression analysis showed that the Redlich-Peterson and Langmuir isotherm models described the equilibrium data reasonably well (coefficient of determination, R 2 > 0:90 in most cases). The Freundlich model, however, was found to be relatively poor (R 2 < 0:90 in most cases) for explaining the adsorption equilibrium in this study. Thermodynamic parameters of the adsorption further confirmed the exothermic nature of the adsorption process as did the negative heat of enthalpy, accompanied by a negative value of entropy change. The overall Gibbs free energy change during the adsorption process was negative for the experimental range of temperatures, corresponding to spontaneous adsorption.
Postharvest Biology and Technology, 2012
Metabolic stress disinfection and disinfestation (MSDD) is a relatively new quarantine treatment ... more Metabolic stress disinfection and disinfestation (MSDD) is a relatively new quarantine treatment in which fruit are exposed to rapid decompression and compression cycles and high CO 2 atmosphere, followed by exposure to ethanol vapour under decompression. This study evaluated the ripening response of 'Hayward' kiwifruit (Actinidia deliciosa) and 'Pink Lady' apple (Malus x domestica) to MSDD treatment, which can control longtailed mealybug (Pseudococcus longispinus). Following the treatments, fruit were held at 20 • C for 7 d for shelf-life assessment, while the remainder were refrigerated at 0.5 • C for 16 weeks. Respiration rate, volatile (ethylene, ethanol and acetaldehyde) production rates, firmness and disorders were measured at regular time intervals. MSDD treatments did not affect the metabolic activities and quality of 'Pink Lady' apples. However, firmness was reduced by 4.9 N in non-refrigerated MSDD treated fruit. MSDD treatments did not control superficial scald disorder in refrigerated 'Pink Lady' apples. For 'Hayward' kiwifruit, treatments increased the respiration rate and ethylene production of short-term refrigerated fruit, promoted endogenous production of ethanol and acetaldehyde in both short-term and long-term refrigerated fruit. MSDD treatments also increased the incidence of rots in refrigerated 'Hayward' kiwifruit. MSDD treatments accelerated the softening of short-term refrigerated kiwifruit, but retarded the softening of 'Hayward' kiwifruit during the 16 weeks of refrigerated storage. MSDD could potentially be used as a quarantine treatment of apples. Further studies are required on the sensory effect of MSDD treatment.
Journal of Food Engineering, Mar 1, 2004
In this study, vitamin E was separated from palm fatty acid distillate by batch adsorption using ... more In this study, vitamin E was separated from palm fatty acid distillate by batch adsorption using an orbital shaker. Silica was used as the adsorbent. Equilibrium of the adsorption process as a function of reaction temperature, agitation rate and silica mass on vitamin E adsorption onto silica was investigated over a range of vitamin E concentration. Lower reaction temperature led to higher vitamin E uptake at equilibrium, indicating that the adsorption process in this study was exothermic. Adsorption capacity increased with the rise in agitation rate. However, in this study the maximum adsorption capacity remained unchanged when silica mass was increased. Generally, non-linear regression analysis showed that the Redlich-Peterson and Langmuir isotherm models described the equilibrium data reasonably well (coefficient of determination, R 2 > 0:90 in most cases). The Freundlich model, however, was found to be relatively poor (R 2 < 0:90 in most cases) for explaining the adsorption equilibrium in this study. Thermodynamic parameters of the adsorption further confirmed the exothermic nature of the adsorption process as did the negative heat of enthalpy, accompanied by a negative value of entropy change. The overall Gibbs free energy change during the adsorption process was negative for the experimental range of temperatures, corresponding to spontaneous adsorption.
Food science and engineering, Mar 25, 2022
Hericium mushrooms are well known for their numerous medicinal benefits, of which neuroprotective... more Hericium mushrooms are well known for their numerous medicinal benefits, of which neuroprotective and anticarcinogenic characteristics are two of the most reported properties. This review summarizes the research advances and techniques used to study these two advantages of Hericium mushrooms reported in the latest 20 years, namely between the years 2001 and 2021. Based on published research, the Hericium-unique compounds (e.g., hericenones and erinacines) and polysaccharides are the main active constituents associated with these two properties. It was reported that about 70 such secondary metabolites were characterized to help prevent or treat neurological and tumor diseases. We have collated the above information in order to provide insights for further studies aiming to maximize the application of Hericium mushrooms as functional ingredients for neuroprotection and anticarcinogenesis.
Food Chemistry, Aug 1, 2012
This study describes the potential use of New Zealand seaweed extracts as antioxidants in fish oi... more This study describes the potential use of New Zealand seaweed extracts as antioxidants in fish oils. The extracts from two brown seaweeds (Ecklonia radiata, Macrocystis pyrifera) and two red species (Champia sp. and Porphyra sp.), were added to hoki (Macruronus novaezelandiae) oil and assessed by production of oxidation products in an elevated temperature (60 °C) storage trial. Antioxidant assays ORAC and DPPH were conducted to elucidate the radical scavenging activity of the seaweed extracts. The results showed that all the lipid-soluble seaweed extracts had some antioxidative capacity, with brown algae generally outperforming red algae species. Extracts from E. radiata performed best with significantly lower primary, secondary and total oxidation products, and higher DPPH radical scavenging ability than the commercial antioxidant, BHT. This study demonstrated the potential of brown algae seaweed extracts, in particular E. radiata, for use as antioxidants in fish oil products.
Uploads
Papers by Siew Young Quek